Screening conveyor

ABSTRACT

A screening conveyor for sifting out undersized fruit and breaking up and sifting out clods of dirt or similar materials includes longitudinally spaced drive and idler pulley shafts with each shaft mounting a row of different diameter pulleys on one shaft aligned with matched pulleys on the other shaft to form matched pairs of pulleys. V-belts are trained around the matched pairs of pulleys to form a series of troughs of a uniform depth. The drive shaft causes adjacent belts to run at different speeds for churning, sifting and sorting materials supported and advanced by the belt members. U-shaped cleats are spaced along the belt members for assisting in the action and for working on the sides of clods of dirt or the like, carried along in the troughs.

United States Patent 1 Walker [54] SCREENING CONVEYOR [75] Inventor:William B. Walker, Los Gatos,

Calif.

[73] Assignee: FMC Corporation, San Jose, Calif.

[22] Filed: Aug. 24, 1970 [21] Appl. No.: 66,512

[52] 11.8. C1 ..209/307, 209/102 [51] Int. Cl. ..B07b 1/10 [58] Field ofSearch ..209/92, 102, 307, 308; 171/12; 198/190 [56] References CitedUNITED STATES PATENTS 86,190 1/1869 Terhune ..209/307 1,585,461 5/1926Brackett ..209/307 X 636,762 11/1899 Conley ..209/307 937,213 10/1909Mash ....209/307 X 1,276,005 8/1918 Barr ..209/307 1,062,775 5/1913Farrar ....209/102 1,735,795 11/1929 Robbins ..209/102 2,547,473 4/1951Klem ..309/307 X 2,979,199 4/1961 Higgins... ....209/102 X 1,204,68511/1916 Phillips ..209/102 2,350,691 6/1944 Mauroner.... ..209/1022,444,466 7/1948 Peterson ..209/385 X FOREIGN PATENTS OR APPLICATIONS65,849 4/1924 Sweden ..209/102 279,307 1/1966 Australia ..209/102734,944 8/1955 Great Britain ..209/102 Primary Examiner-Frank W. LutterAssistant Examiner-Robert Halper Attorney-F. W. Anderson and C. E. Tripp[57] ABSTRACT A screening conveyor for sifting out undersized fruit andbreaking up and sifting out clods of dirt or similar materials includeslongitudinally spaced drive and idler pulley shafts with each shaftmounting a row of different diameter pulleys on one shaft aligned withmatched pulleys on the other shaft to form matched pairs of pulleys.V-belts are trained around the matched pairs of pulleys to form a seriesof troughs of a uniform depth. The drive shaft causes adjacent belts torun at different speeds for churning, sifting and sorting materialssupported and advanced by the belt members. U-shaped cleats are spacedalong the belt members for assisting in the action and for working onthe sides of clods of dirt or the like, carried along in the troughs.

4 Claims, 8 Drawing Figures PATENTEnJAnao I973 SHEET 1 BF 4 INVENTOR.WILLIAM B. WALKER ATTORNEYS PATENTEU JAN 30 I973 SHEET 2 BF 4 m -lM-mlhiwl PATENTEnJAuso I973 3.7 1 3. 537

sum 3 BF 4 FIEI E Fll3 q B SCREENING CONVEYOR REFERENCE TO RELATEDAPPLICATIONS A screening conveyor of the general type disclosed andclaimed herein is shown in a harvester for tomatoes or the like in thecopending application of Cayton et al., Ser. No. 49,415, filed June 24,1970 (SJ 5592) now U.S. Pat. No. 3,613,796, issued Oct. 19, 1971.

DESCRIPTION OF PRIOR ARTS Cerruti U.S. Pat. No. 534,783, issued Feb. 26,1895, shows divergent grading belts driven by different sized pulleys onthe same drive shaft. There is some slight vertical spacing of the beltsas they leave the drive shaft, but this is negligible and this is soontaken out by a first set of idler rollers.

Farrar et al. U.S. Pat. No. 1,062,775, May 27, 1913, discloses ropesdriven in the same plane and at the same speed flanked by a pair ofchains having cleats thereon and driven in a direction opposite to thatof the ropes.

Wade et al. U.S. Pat. No. 1,552,366 Sept. 1, 1925, has alternately largeand small drive pulleys on a drive shaft with all belts passing overupper idlers of the same diameter so that although the belts are drivenat different speeds they lie in a common plane at their conveyingsurfaces.

Robbins U.S. Pat. No. 1,735,795, Nov. 12, 1929, forms fruit gradingtroughs by the use of three belts, the upper two of which graduallydiverge from the central belt in a vertical plane. All belts are drivenat the same speed. The U.S. Pat. to Whisnand et al., No. 1,888,709, Nov.22, 1932, shows a similar arrangement.

Mauroner U.S. Pat. No. 2,350,691, June 6, 1944, shows a berry graderwherein the belts are all at the same level and driven at the same speedwith small wire-like cleats wrapped around the convex upper surfaces ofthe belts. The aforesaid U.S. Pat. to Farrar et al. No. 1,062,775 alsoshows small wire-like cleats projecting upwardly from chain members.

Klern U.S. Pat. No. 2,547,473, Apr. 3, 1951, shows belts driven atdifferent speeds by a shaft at one end driving one set of belts and ashaft at the other end driving another set. The belts are in the sameplane.

Higgins, Sr. U.S. Pat. No. 2,979,199, Apr. 11, 1961, mounts a pluralityof pulleys which gradually vary in diameter on spaced shafts to form asinusoidal contour for the conveying surface. The pulleys for each beltare not matched pairs so that the troughs formed taper out at theirmid-lengths and the disparity in vertical displacement .of adjacentbelts is small. Material flows laterally of the belts in this reference.

SUMMARY OF THE INVENTION Although the sorting conveyor of the presentinvention is of more general utility, it will be described in connectionwith the handling of loose dirt, clods of dirt and loose tomatoes suchas that supplied by a tomato harvester in the copending application ofCayton et al., Ser. No. 49,415, filed June 24, 1970'(SJ 5592) now U.S.Pat. No. 3,613,796, issued Oct. 19, 1971, assigned to the FMCCorporation. A similar utilization of the sorting conveyor of thepresent invention would be in connection with tomato harvesters such asthose of the U.S. Pats. to Looker No. 3,031,331, issued Jan. 31,

1967 and Csimma, No. 3,340,935, issued Sept. 12, 1967 and assigned tothe FMC Corporation.

In the utilization of the invention in connection with sorting tomatoes,a mass of loose fruit, clods of dirt and loose dirt is received from aconveyor and passed on for sorting. This sorting involves removal ofundersized fruit as well as clods of dirt so that the remaining marketsized fruit can be inspected and finally sorted. Under the presentinvention, while the mass of loose material is advanced along theconveyor, it is subjected to a churning and clod breaking action, aswell as a sifting and screening action. As a result, not only areundersized fruits dropped out along with loose dirt, but large clods arebroken up into smaller clods which, in turn, drop out along with thedirt and undersized fruit. This leaves only market sized fruit forfurther inspection along with some clods which are too large to havebeen broken up and screened out by the conveyor. The large clods do notrepresent a serious sorting burden.

The aforesaid action on the loose material is provided by forming theconveyor reach as a group of laterally spaced V-belts moving atdifferent speeds and at alternately different elevations. Thus threebelt troughs are formed along the lengths of the conveyor which exposethe materials being conveyed to action from the side along the entirelength of the conveyor. This provides a churning and tumbling of thematerial and hence insures that all of the fruit will settle to thebelts so that undersized fruit can be dropped out between the belts.Likewise, this side action is exerted on the clods of dirt and tends topulverize them and reduce them to a size sufficiently small so that theytoo will be sifted out along the length of the screening conveyor. Theaforesaid action on clods of dirt is facilitated by the provision ofU-shaped cleats that project laterally past the edges of the belts andare spaced longitudinally along the belts. These cleats are providedwith side digging edges which work upon the clods and pulverize them asmentioned above.

When the conveyor is used to screen field crops that are mixed withdirt, the essential cleaning of the parts is provided by fixed scrapertongues projecting into the V-belt grooves in the pulleys. Also notchedscraper tongues scrape the return reaches of the V-belts clean.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan of a conveyor systemembodying the unit.

FIG. 2 is a section on line 22 of FIG. 1.

FIG. 2A is a section on line 2A-2A of FIG. 2.

FIG. 3 is a section on line 3-3 of FIG. 2.

FIG. 4 is a section of line 4-4 of FIG. 2.

FIG. 5 is a fragmentary enlarged side view of a belt and support rail.

FIG. 6 is a section on line 66 of FIG. 5.

FIG. 7 is an enlarged section on line 7-7 of FIG. 2.

DETAILED DESCRIPTION Referring to FIGS. 1 and 2, in a system forutilizing the present invention,loose material, including objects suchas large or market sized fruit F (FIG. 7), smaller undersized fruit f,loose dirt and large clods of dirt D are introduced into the system by afeeder conveyor A, having a belt 10, a delivery roller 12 and supportingbrackets 14 for the roller. Details of the conveyor A are not criticalto the present invention and the conveyor may be of conventionalconstruction.

The body of loose material introduced by the conveyor A is distributedacross the screening conveyor B of the present invention wherein thesorting, sifting and clod breaking action previously mentioned isperformed. The market sized fruit F, along with a few large clods D aredeposited onto a belt conveyor C for further processing. The beltconveyor C may be a sorting conveyor or may lead to a sorting system asin the aforesaid copending application of Cayton et al or the aforesaidLooker and Csimma patents. If the conveyor C is itself a sortingconveyor, a platform P (FIG. 1) can be provided alongside of thatconveyor to provide a sorting station for the desired number of sortingoperators.

The screening conveyor B of the present invention is mounted betweenside plates 16 and 17 and has an end plate 18. Extending between theside plates are a drive shaft 20 and an idler shaft 22, the spacingbetween the shafts being sufficient to provide the necessary sorting andclod breaking action. This spacing is not critical to the presentinvention it only being necessary that these shafts be spaced far enoughto suit the nature of the materials being handled by the conveyor B.

Mounted along the shafts 20 and 22 are matched pairs of V-belt pulleysof alternately varying diameter, there being a row of such pulleys oneach shaft. For example, in the embodiment being described, the drivingshaft 20 (reading from the bottom of FIG. 1) has pinned or keyed theretoa large V-belt pulley 24, a small pulley 26, an intermediate pulley 28,another small pulley 26, a second large pulley 24, a third small pulley26, and a second intermediate pulley 28. The drive shaft 20 is driven bya hydraulic motor 30 which is connected to a pump and a variable speedcontrol system (not shown) in a conventional manner not critical to thepresent invention.

The idler shaft 22 has mounted therein pulleys 24a, 26a, 28a, 26a, 24a,26a and 28a, in the order named, to form matched pairs with theircounterparts on the drive shaft 20. The pulleys are mounted for freerotation on the shaft 22.

V.-belts 34 are trained over the large pulleys 24, 24a, V-belts 36 aretrained over the small pulleys 26, 26a and V-belts 38 are trained overthe intermediate pulleys 28, 28a. As a result of the varying diametersbetween adjacent matched pairs of pulleys, three-belt triangles areformed (FIGS. 3 and 7) and rotation of the drive shaft 20 impartsdifferent linear speeds to the V-belts for each trough as indicated bythe lengths of arrows placed on three of the belts in FIG. 1.

In order to minimize interference with materials dropping between thebelts, not all of the lower reaches of the belts return in the sameplane. For example, the belts 34 that pass over the larger pulleys 24,240 also pass over idlers 44 below the pulleys 24a (FIGS. 2 and 3).These idlers are mounted on brackets 46 which may be adjustablypositioned along horizontal posts 48 mounted in the end plate 18 of themachine. This ad justment also serves for taking up tension on the belts34. Similarly, the belts 38 that pass over the intermediate pulleys 28,28a are trained over idlers 54 mounted in brackets 56 adjustably securedon frame posts 58.

In order to prevent the upper, conveying reaches of the belts 34, 36 and38 from sagging under the weight of the material they must carry,T-shaped support rails 64, 66 and 68 are provided beneath the upperreaches of the belt 34, 36 and 38 respectively. The rails 64, 66 and 68are supported at their ends by means of downwardly projecting ears 64a,66a and 68 a (FIGS. 2 and 7) which receive transverse rods 69 and 70(see also FIG. 1) extending between the side plates 16 and 17.

In order to guide the belts laterally along their paths while supportingthem on the T-rails just described, clips 72, 74 are riveted to thevertical portion if the T- shaped rails, a clip assembly on the rail 64being shown in detail in the enlarged views of FIGS. 5 and 6. Theseclips extend upwardly through apertures 72a, 74a in the horizontalportion of the rails, as seen in FIG. 6.

In order to advance the material along the belts, and work the materialfrom below, as well as to work it from the sides as it rests in thetroughs formed by the alternate bearing diameter pulleys, cleats aremounted along the belts. The details of a cleat mounted on a belt 34 areillustrated in FIGS. 5 and 6. Each cleat comprises a U-shaped member 82having a transverse leg 84 and depending vertical legs 86, 88. A rib 90,preferably made of plastic or rubber, is bonded to the transverse cleatleg 84. The cleats are fastened to their associated belts by rivets 92,the riveted ends of which may be recessed within the conventionalnotches 9, formed in V-belts of this type. As seen in FIG. 7, thelateral extent of the cleats is such that the depending legs 86, 88 comeclose to passing one another in a common vertical plane. This action notonly provides a side digging action, but also presents leading edges ofboth the horizontal portion 84 and the vertical portions 86, 88 of thecleats to dirt or clods of the like to assist in the pulverizing orbreaking action characteristic of the present invention.

SCRAPERS Since considerable wet soil is introduced to the sorter of thepresent invention in the case of field harvesting, under thesecircumstances belt and pulley scrapers are provided. Referring to FIGS.2 and 2A, the grooves of pulleys 24a, 26a and 28a are scraped clean bytongues 92, 94 and 96 respectively, projecting from a mounting bar 98.

The grooves of pulleys 24, 26 and 28 are scraped clean by tongues 102,104, 106 respectively, projecting from the belt support rails 64, 66 and68.

The grooves of idlers 44 and 46 are scraped clear by tongues 112 mountedon ears 114 projecting from the pulley mounting brackets 46, 56.

The belts 34, 38 are scraped clean by notched fingers on the ears 114and the belts 36 are scraped clean by notched fingers 116 projectingdown from the bar 98.

TYPICAL EXAMPLE The following design considerations are given as atypical screening conveyor embodying the invention and suitable forhandling tomatoes:

Diameter of pulleys 24, 24a 5.5 inches.

Diameter of pulleys 26, 26a 3.5 inches.

Diameter of pulleys 28, 28a 4.5 inches.

Linear speed of belts 34 120 ft/min.

Linear speed of belts 36 76 ft/min.

linear speed of belts 38 98 ft/min.

Minimum spacing of shaft 20, 22- 4 feet.

Lateral gap between vertical planes of U-belt side edges 1.125

OPERATION In operation when a sorter of the present invention is used inconjunction with the handling of tomatoes in the manner mentionedpreviously, a mass of materials including market tomatoes F, undersizedtomatoes f, loose dirt, clods of dirt D and other material is depositedby the feeder conveyor A and spread across the receiving end of thescreening conveyor B, of the present invention. This material works itsway into the various three-belt troughs provided by the matched pairs ofpulleys of alternating diameters characteristic of the presentinvention.

The belts that define each trough run at mutually different linearvelocities, as shown by the three arrows at the top center of FIG. 1.This exerts a turning, tumbling and churning action on the mass, causingthe smaller objects to sift through the mass and the belts, and thelarger objects to rest on the belts.

As seen in FIG. 1, a vigorous churning action is also provided becauseof the provision of the three-belt troughs, with adjacent belts runningat different linear velocities. The cleats 80 provide a dual action onthe materials. Those cleat portions at the bottom of each trough rolland tumble the clods D and the tomatoes thereby facilitating thescreening action so that the smaller tomatoes f will drop throughbetween the belts and onto the ground or other receptacle. This rollingaction does not damage the tomatoes.

In addition to the action described above, the downwardly projectinglegs 86, 88 of the cleats 80 engage the sides of clods D and erode orbreak away sections of the clods so that some of them fall down betweenthe belts and are thereby eliminated from the system before the finalsorting or inspection operation. Of course, the depending legs 86, 88also engage the larger tomatoes F along the sides of the latter, butsince these objects (unlike the clods) essentially have surfaces ofrevolution, they are merely cammed and rolled aside by the cleats andare not cut or damaged thereby.

Although the best mode contemplated for carrying out the presentinvention has been herein shown and described, it will be apparent thatmodification and variation may be made without departing from what isregarded to be the subject matter of the invention.

What I claim is:

1. A screening conveyor for separating dirt and small objects from amass of fruit or the like said conveyor being of the type comprisinglongitudinally spaced horizontal pulley shafts, each shaft mounting arow of pulleys of varying diameters, the pulleys of a given diameter onone shaft being aligned with those of the corresponding diameter on theother shaft to form pairs of matched diameter pulleys, belt memberstrained around each matched pair of pulleys with the upper reaches ofsaid belt members being parallel and substantially horizontal, and meansfor driving all pulleys at the same rotational speed; the improvementwherein said belt members are rubberized V-belts and the pulleys on eachshaft are arranged in a plurality of groups,

each group comprising three pulleys, namel a central small diameterpulley, a large diameter pu ey on one side of the small pulley, and anintermediate diameter pulley on the other side of said small pulley sothat said group of pulleys provide differential speeds to adjacentbelts; and a plurality of longitudinally spaced cleats mounted over andto said belts, said cleats projecting laterally past both sides of theirrespective belts to provide differential speed, material churning sideedges, particles of dirt or the like and small objects dropping outbetween the upper regions of said belts whereas larger objects areretained on and discharged from the belt.

2. The screening conveyor of claim 1, wherein said cleats are U-shapedwith their side edges being substantially at least as long as theadjacent sides of the belts on which they are mounted.

3. The screening conveyor of claim 2 wherein the side edges of saidcleats on adjacent belts run substantially in a common vertical plane.

4. The screening conveyor of claim 1, including auxiliary idler pulleysfor alternate belts disposed below the shaft at the material receivingend of the conveyor, thereby providing lower, return belt reaches thatrun downwardly from the pulleys on the shaft disposed at the materialdelivery end of the conveyor.

1. A screening conveyor for separating dirt and small objects from amass of fruit or the like said conveyor being of the type comprisinglongitudinally spaced horizontal pulley shafts, each shaft mounting arow of pulleys of varying diameters, the pulleys of a given diameter onone shaft being aligned with those of the corresponding diameter on theother shaft to form pairs of matched diameter pulleys, belt memberstrained around each matched pair of pulleys with the upper reaches ofsaid belt members being parallel and substantially horizontal, and meansfor driving all pulleys at the same rotational speed; the improvementwherein said belt members are rubberized V-belts and the pulleys on eachshaft are arranged in a plurality of groups, each group comprising threepulleys, namely, a central small diameter pulley, a large diameterpulley on one side of the small pulley, and an intermediate diameterpulley on the other side of said small pulley so that said group ofpulleys provide differential speeds to adjacent belts; and a pluralityof longitudinally spaced cleats mounted over and to said belts, saidcleats projecting laterally past both sides of their respective belts toprovide differential speed, material churning side edges, particles ofdirt or the like and small objects dropping out between the upperregions of said belts whereas larger objects are retained on anddischarged from the belt.
 1. A screening conveyor for separating dirtand small objects from a mass of fruit or the like said conveyor beingof the type comprising longitudinally spaced horizontal pulley shafts,each shaft mounting a row of pulleys of varying diameters, the pulleysof a given diameter on one shaft being aligned with those of thecorresponding diameter on the other shaft to form pairs of matcheddiameter pulleys, belt members trained around each matched pair ofpulleys with the upper reaches of said belt members being parallel andsubstantially horizontal, and means for driving all pulleys at the samerotational speed; the improvement wherein said belt members arerubberized V-belts and the pulleys on each shaft are arranged in aplurality of groups, each group comprising three pulleys, namely, acentral small diameter pulley, a large diameter pulley on one side ofthe small pulley, and an intermediate diameter pulley on the other sideof said small pulley so that said group of pulleys provide differentialspeeds to adjacent belts; and a plurality of longitudinally spacedcleats mounted over and to said belts, said cleats projecting laterallypast both sides of their respective belts to provide differential speed,material churning side edges, particles of dirt or the like and smallobjects dropping out between the upper regions of said belts whereaslarger objects are retained on and discharged from the belt.
 2. Thescreening conveyor of claim 1, wherein said cleats are U-shaped withtheir side edges being substantially at least as long as the adjacentsides of the belts on which they are mounted.
 3. The screening conveyorof claim 2 wherein the side edges of said cleats on adjacent belts runsubstantially in a common vertical plane.